Zeolites are widely used as acidic catalysts for refining applications attributed to their unique and uniform pore structure with sizes in the sub-nanometer range. The pore sizes of zeolites dictate reaction of refining processes including hydroisomerization, hydrocracking, olefin alkylation and olefin oligomerization, thus dictate reaction selectivity. However, hydroprocessing products often experience varying degree of continuously (over)cracking when they diffuse out of nanometer-scaled zeolitic channels. Thus elimination of these types of side-reactions is significant for efficiency improvement. One of the solutions for preventing overcracking is reduction of acidic strength. But this approach reduces catalyst activity at the same time.
A. Corma et al. in “Delaminated zeolite precursors as selective acidic catalysts”, Nature, vol. 396, November 1998, pp 353-356, discusses delaminating MCM-22(P), the precursor of both MCM-22 and ERB-1 zeolites. The delaminated zeolite is designated ITQ-2, and was shown to have catalytic potential.
Molecular sieve SSZ-70 is known and is discussed in “Physiochemical Properties and Catalytic Behavior of the Molecular Sieve SSZ-70”, Archer et al. Chemistry of Materials, 2010, vol. 22, pp 2563-2572. A method for the synthesis of the SSZ-70 is discussed. Pure silica, borosilicate and aluminosilicate SSZ-70 materials were prepared and characterized. The catalytic activity of Al-SSZ-70 materials was tested using the CI (Constraint Index) test. U.S. Pat. Nos. 7,108,843 and 7,550,073 also discuss the synthesis of the molecular sieve SSZ-70, and its use in hydrocarbon conversion processes such as hydrocracking. The disclosure of both U.S. Pat. Nos. 7,108,843 and 7,550,073 are expressly incorporated herein by reference in their entirety.
It would be of great value to the hydroprocessing industry if a more effective and selective olefin oligomerization process were discovered.